This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or 365 to Patent Application Serial No. 0101419-0 filed in Sweden on Apr. 24, 2001, the entire content of which is hereby incorporated by reference.
1. Technical Field of the Field
This invention relates to a cutting tool intended for parting and grooving operations of the type that comprises a holder for a narrow cutting insert which is clampable in a seat between a blade tongue and a clamping finger protruding as extensions of the lower and upper front parts of the holder. The front parts are thicker than the blade tongue and the clamping finger and are spaced-apart by a gap which enables swivelling of the front partsxe2x80x94and thereby also the blade tongue and clamping finger, respectively, in a direction towards each other from a starting position, more precisely by means of a clamping mechanism mounted in the holder.
2. Prior Art
Cutting tools of the above-mentioned type are used for grooving, parting, or other operations in which grooves are turned in rotating workpieces, primarily workpieces of metal. A general aim is to form the cutting insert as narrow as possible (with modern technology, the cutting inserts may have a thickness as small as 1-2 mm). For this reason, the blade tongue and the clamping finger have a thickness or width, which amounts to only a fraction of the width of the holder.
In previously known cutting tools of the type in question (see, for instance, U.S. Pat. No. 5,411,354), the clamping mechanism has the form of a simple screw which is inserted from above into a bore in the upper front part and screwed tight into a threaded hole in the lower front part, whereby the head of the screw is accessible from the top side of the upper front part. This entails problems in such applications where it is desirable to mount a plurality of cutting tools close to each other in the same plane so far that it becomes difficult to insert and manipulate a key in the limited space between neighboring tools. The disadvantages of the unsatisfactory accessibility of the tightening screws become particularly apparent with small cutting tools of the type called xe2x80x9cSwiss Tools.xe2x80x9d Another disadvantage of the previously known cutting tools is that the tightening torque of the tightening screw, and thereby the clamping force of the cutting insert, cannot be determined in any well-defined way.
The present invention aims at obviating the above-mentioned disadvantages of previously known cutting tools for parting and grooving operations and at providing an improved cutting tool of this type. Therefore, a primary aim of the invention is to provide a cutting tool, the clamping mechanism of which is conveniently accessible for a key or the like also in such cases when a plurality of tools are mounted near each other. An additional aim is to create a cutting tool, the clamping mechanism of which should be structurally simple and which works in a reliable manner, whereby the correct clamping force on the cutting insert is obtained in a simple manner, more precisely without the operator needing to devote mental effort to this problem in connection with the continuous repetitive change of cutting inserts.
The present invention relates to a cutting insert holder which comprises a body forming upper and lower front parts that are spaced apart by a gap to enable the upper and lower front parts to move toward one another. A tongue projects from the lower front part, and a clamping finger projects from the upper front part and overlies the tongue in spaced relationship thereto to form an insert seat therebetween. The clamping finger and the tongue are narrower than each of the upper and lower front parts. The tongue and the clamping finger are movable toward one another as the upper and lower front parts move toward one another. A clamping mechanism is disposed in the body and includes a drawbar and a tightening screw. The drawbar extends slidably through a bore formed in one of the upper and lower front parts and is fixedly secured to the other of the upper and lower front parts. The drawbar includes a head having an abutment surface. The tightening screw is threadedly connected to the body and projects into the one of the upper and lower front parts at an angle relative to the bore and has first and second end sections. The first end section is accessible to a tool for rotating the tightening screw to advance the tightening screw in a direction for bringing the second end section thereof into engagement with the abutment surface to displace the drawbar relative to the one of the upper and lower front parts in a direction forcing the tongue and the tightening finger toward one another.